桥联模型发展的若干基本问题研究

破坏和强度，是结构材料的最重要特性，而复合材料的破坏和强度分析，却被认为是固体力学面临的一个最大挑战。现有的破坏和强度理论，主要基于唯象方法建立，但复合材料层内和层间破坏的几个基本问题：界面开裂、纤维破坏、基体断裂、层合板分层，都必须借助细观力学才能解析清楚。细观力学预报复合材料破坏和强度，还可将对复合材料实验数据的依赖性降到最低。与其他细观力学方法相比，桥联模型的优势显著，尤其是基于桥联模型创建的基体真实内应力理论，对复合材料的破坏和强度分析将不可或缺。本项目旨在进一步发展桥联模型，揭示任意载荷下的界面开裂机理，建立纤维的压缩破坏判据和基体的统一强度理论，实现基于组分性能的分层萌生预报，使复合材料层内与层间破坏的几个基本问题都能获得较好解决，并完善基体原始性能的确定方案，提高复合材料破坏和强度的预测精度，对复合材料力学学科发展具有重大科学意义，而且工程应用前景广阔。

Failure and strength is the most important property of a structural material. Yet, an analysis for failure and strength behavior of a composite is grossly considered to be one of the biggest challenges in solid mechanics. Most failure and strength theories for composites have been established phenomenologically. However, the fundamental problems of intralaminar and interlaminar failures of a composite, i.e., interface crack between fiber and matrix, fiber failure, matrix breakage, and delamination, cannot be analyzed clearly without using a micromechanics approach. Furthermore, the micromechanics approach to composite failures can reduce the dependence on experimental data of the composites to the minimum. Compared with other micromechanics theories, Bridging Model has shown its obvious advantages. Especially, the theory for the true internal stresses of the matrix established on Bridging Model will be indispensible in the failure and strength analysis of a composite. The aim of this project is to further advance the Bridging Model, in order that the interface crack mechanism can be efficiently explored, compressive failure criteria for fibers and a unified strength theory for any kind of matrix failures can be established, and micromechanical prediction on delamination initiation of laminates essentially using only original fiber and matrix properties can be achieved. In addition to these fundamental intralaminar and interlaminar failure problems to be well addressed, a correct procedure to determine the original matrix properties specifically failure and strength behaviors will be obtained in this project as well. The accomplishment of this project will increase the accuracy in failure and strength prediction for composites. Not only will it show significant importance for the development of mechanics of composites discipline, but also it will has a broad application future in engineering.